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Jonathan writes "Today, the 14th of March, is Pi Day 2008. Pi Day is internationally celebrated in honor of the mathematical constant "Pi," who's actual value will — now and forever — remain unknown. NeoSmart Technologies has a run-down on the history of Pi, Pi Day, and the significance of Pi and other such "magical numbers" to science and technology. 'Pi isn't just a number that you can use to calculate circle-related mathematics, it's a symbol of something by far greater. Pi is one of many "magic" numbers that are found everywhere — if you know where to look. These magic numbers can't be explained, they just are. And if you use them right, they make it a lot easier to do a lot of really complicated things... In a way, they're a testimony to technology and computers (or vice-versa, depending on how you look at it).'"

Sorry, but we missed Pi day by a longshot. Having Pi day on any old 3/14 lacks sufficient precision. Pi day was on March 14, 1592. Pi second would have been March 14, 1592 at 6:53 and 58 seconds in the morning. I'm sure they were partying like it was 1599 on that day.

In the universally preferred notation (except for those who take being non-conformist to absurd levels), you'll mean the year 3141, May 9th at 2:53.58am in the morning.

So we didn't miss it - but we will be missing it, as none of us are going to be living to be that old.

Then again, this is all based on the current calendar (arbitrary) and how you interpret the numbers (arbitrary) as well as the date/time notation (arbitrary, as pointed out above) ( the last two being related to eachother as there's no, say, 31st of april.)

Fortunately for those of us in the rest of the world where we use the more logical d/m/y time ordered notation we still have a couple of thousand years to go: 3/1/4159. It would have been earlier but April only has 30 days!

True story: two of my high school's math teachers used to make sure that we got French Silk pie on Pi Day and 2^10 Day (October 24th [wikipedia.org], of course), with a bit of extra math fun (games, etc.) unrelated to the topic at hand. Sure, it's a bit of a corny idea, but we appreciated that little "extra step" they took to make math more approachable, beyond their excellent guidance.

Never say "I didn't sleep enough" - the correct way to say it is "It was observed that my sleep duration was less than average." Or (In Plank units), "I have a sleep deficiency of about ten to the power 47, which is about half an hour."

And following up TLAP Day is the oft overlooked Talk Like A Physicist to Girls Day, observed by spending the day blushing while staring at your toes, occasionally clearing your throat, and sputtering out the occasional "awe shucks".

The evidence at hand would seem to indicate that your verbage is non standard for a physicist. It fits the template of a pirate with insomnia, though. Without further data I am only speculating of course.

I would not say that it has an unknown value, the value is known as the ratio of a circle's diameter and circumference. Just because our system of representing numbers is flawed in that it cannot accurately define numeric sequences that approach infinity doesn't mean it is unknown... That is like saying 1/3 is unknown just because you can't print enough 3's after the decimal place to be accurate.

I'm sorry because I know I'm being pedantic, but I've dealt a fair amount with number theory and I felt like I should comment. You can't, strictly speaking, have "base pi" in the way that our number system is "base 10". If you don't quite know why that is the case, ask yourself if you wanted to count to "10" in "base pi" (which would be pi), what would that counting look like?

If you think it would be "1, 2, 3, 10" then you're talking about base 4. Otherwise, the distance on a number line between 0->1, 1->2, and 2->3 would all be equal to one unit, but 3->10 (the next number) would be 0.14159265... units.

The issue of pi being an irrational number, rather, is related to the definition of numbers as geometric ratios (which is how most of our mathematics consider numbers). The problem is that the diameter of a circle and the circumference are incommensurable, meaning that you can never come up with a whole-number ratio between those two lengths. Therefore, you cannot, no matter what length you choose as your unit, measure both the diameter and circumference with the same unit.

As a result, we generally take the diameter to be 1 unit of length, and the length of the circumference to be represented by the irrational number pi units of length. So the "number" of pi is an approximation of the ratio of diameter:circumference. We could just as easily assign the circumference to be the unit, however, and then the measurement usually represented by pi would be represented by "1" (which is what I think the GP post was alluding to). However, this would result in us having to deal with a different irrational number, which would be for representing the diameter, which would be 1/pi.

You can't do *discrete* math base pi, but there's plenty of other math you can do.

You can do non-integer bases, but it gets interesting. Non-rational bases get even more interesting. Maybe not practical for much, and you can't represent the "normal" integers usefully, but it's still a field and all of the abstract algebra still works.

But no system of representing numbers could express pi's relationship to 1 exactly without an infinite amount of information. We can express a method of calculating pi, for instance, but the method must necessarily have an infinite number of steps. That means the value cannot be found exactly, so in some sense it is very much "unknown".

"infinite amount of information"? Only if you're the sort of person who calls any bigger-than-linear increase "exponential". Words have meanings, and scientific/mathematical words have very precise meanings.

Here's a complete representation of the value of \pi:

4\sigma_{k=1}^\infinity\frac{(-1)^{k+1}}{2k-1}

That's only 368 bits of information, and I'm sure there are more compact encodings of the value.

But no system of representing numbers could express pi's relationship to 1 exactly without an infinite amount of information.

What is it about the symbol for pi that makes it more or less special than the symbol '3', or either of their relationships to the symbol '1'?

There's a whole lot of math you can do using the symbol for pi to stand for the ratio between a circle's radius and circumference. The fact that it doesn't look like the symbols for decimal integers doesn't hurt it any; in fact, for most of

Well, there are unsolved mysteries surrounding the digits of pi. The patterns they follow aren't really known. It is still not known weather they are uniformly-distributed. So we don't know them all, and we don't really know how they behave.

Compare that to the digits of 1/3 = 0.3333... They are pretty well known.

Weather pi is "unknown" or not is kind of an undefined question. By definition it is not. By the cool formulas we know how to get better approximations of it, it is not. By the behavior and dist

Pi's value is known totally precisely, it is just that an irrational number cannot be represented using the good ol' rational numbers or any x/y form of them, it only can be approximated. That is why it is called an irrational number! It doesn't make pi any less definite though.

I think it does in a sense. Pi is precisely defined: it's the number that you get when you divide the circumference of a circle by its diameter. But that's not its value, that's its definition. And then we say, "Oh and look at all the other places it pops up and all of the other things we can do with it." We can say, it's the number that does this. It's the one you get when you do that. But we can't precisely place it on a number line. There is somethin

If you are going to point out an error, at least take the time to provide an example of the correct grammar.

Grammar has always been a weak-point (no hyphen needed) of mine, so it would have been nice if you had finished your thought (assuming your actual goal was NOT just to point out (split infinitive, but that's forgiveable these days)someone else's mistake so you could look clever without actually being helpful).

Don't make me go all George Costanza and have to tell you who (whom: a tricky case this time) the jerk store just ran out of... (Even sentences which end in ellipsis dots need periods!):)

This schema fails if you continue to minutes and seconds:
March 14, 15:92:65

The proper representation is modular-place arithmetic. Instead of assuming each number chunk is either decimal or hundreds, you use the actual size of the place. The Calendar places are:
12 months
31 days
24 hours
60 minutes
60 seconds

The correct international date format uses the ISO format of yyyy-mm-dd - for pi day, it's 31415926535897932384626433832795028841971693993751058209749445923078164-06-28. Unlike the annual celebration, this one day event is something that you won't forget.

Not sure if anyone has mention this book (link : http://www.amazon.co.uk/History-Pi-Petr-Beckmann/dp/0312381859/ref=pd_bbs_sr_1?ie=UTF8&s=books&qid=1205526089&sr=8-1 [amazon.co.uk] )I found it entertaining and easy to read while at the same being informative/interesting. I feel the book gives a very good presentation of the thought process behind how different civilizations reached their approximation of Pi and a good insight into how brilliant people of different times where able to calculate Pi. I bet a lot of "ordinary" people wouldn't have a clue about how to find a good number for Pi, without hitting their "Pi"-button on a calculator:)